The front house has a Cisco WRVS4400n router, providing 2 SSIDs - SSID1 in VLAN1 and SSID2 in VLAN99.

The rear house now needs VLAN1 for an IP-Camera connected to LAN and should repeat SSID2 for public access securely separated from VLAN1.

Besides the router there is a Cisco WAP4410n available for the rear house.

I can't figure out how to accomplish this without buying additional hardware or using workarounds like firewalls. The information i found about WDS bridging, repeating and client modes aren't clear to me.

What is WDS bridging used for? The manual says:

Select to let the access point operate as a
wireless bridge to perform transparent bridging with other associated
wireless bridges, and not allow any wireless client or station to access
them.

So what does the bridge actually do? Is just can't think of a useful scenario...

In WDS Repeater Mode i can not create multiple SSIDs or configure the AP to repeat multiple SSIDs, is this a limitation of the WAP4410n or is it impossible / rare? From the manual:

Select to let the access point operate as a
wireless repeater to extend the radio range of the associated remote
access point to overcome any obstacle that blocks radio communication.